Qualified professionals in science, technology, engineering, and mathematics (STEM) and STEM education are in increasingly short supply globally. Role models can help increase women's representation in STEM, both at entry and senior levels. The study objectives were to identify the characteristics of role models in STEM higher education and careers and to investigate the differences in role model characteristics between career stages and between genders. We used a mixed-methods methodology involving a questionnaire and interviews. The participants, 788 alumni and final-year undergraduate and graduate students from a STEM research university, responded to the questionnaire, and ten leading women in STEM professions were interviewed. The questionnaire results indicated that a higher proportion of women than men reported being influenced by a role model during their studies. Seven key characteristics of role models were identified from the open-ended responses and the interviews: "ambitious," "charismatic," "empathic and encouraging," "inspiring," "knowledgeable," "gifted," and "professional." The most frequent characteristics women mentioned were "empathic and encouraging." The research findings support and align with the social cognitive career theory (SCCT), demonstrating how role modeling, which is part of the environmental theme, boosts intrinsic motivation--part of the personal theme, for individuals in STEM, especially women. These processes impact women's determination and professional performance--part of the behavioral theme. Based on our findings, to advance toward a STEM workforce characterized by greater fairness, we recommend designing and deploying structured mentoring programs and forums in STEM departments that can provide young women with more role models for success and thus with more hope for success in these fields.